Buying Guitar Wood – What to Look Out For
There are some things that you want to avoid when picking out guitar wood. Runout can be a problem as well as highly figured wood. These things can compromise the integrity of the guitar as it ages. And it can be a problem almost immediately if the flaws are pronounced enough.
Building a guitar is a lot of work and takes a long time. Don’t waste your time and efforts using bad materials. Learn what to look out for right away. And don’t be taken in by all the fancy wood grains you see in some guitars. These guitars will almost certainly develop problems at some point because of the wood selection.
Highly Figured Wood
Wild looking, fancy grains may have visual appeal, but they are inherently unstable because they are almost never quarter sawn and can contain defects (more on this in a later installment). So what makes them beautiful also makes them dangerous to use. Problems can arise as the the instrument ages. On guitars, this type of wood should be avoided, especially on guitar backs. Stick to traditional guitar wood. They are traditional for a reason.
What is Runout?
Look at the side grain and you will find grain lines. Ideally these grain lines should run parallel to the top surface the entire length of the board but this is a rarity. Typically these grain lines will run from the top face to the bottom face at some angle. If you pick one of these lines and follow its path, the distance between where the line crosses the top face and the bottom face is the runout (see photo on right).
Why is Runout important?
Because if the distance is short (referred to as short grain) it will not be as strong to a force perpendicular to its face as it would if the distance were longer and it will also have a greater probability of tear out when you plane it. For a neck, I like to choose boards with at least 5 or 6 inches of runout.
Why quarter sawn wood for guitars?
Quarter sawn wood expands and contracts with humidity the least of the three types of cuts and is very strong (if runout is minimal – more on this below) longitudinally (from end to end) making it more resistant to a force applied perpendicular to its face. This makes it useful for guitar tops, backs, sides and necks. Its straight grain also has a very subtle calming and pleasing visual effect. I prefer this look.